• Journal of the Korean Wood Science and Technology
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• v.34 no.5
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• pp.1-10
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• 2006

The objective of this study was to elucidate the microscopic patterns of decay caused by brown-rot fungi of Tyromyces palustri and Gloeophyllum trabeum in Korean red pine (Pinus densiflora) and radiata pine (Pinus radiata) woods through light and electron microscopies. The ultrastructural changes of cell walls attacked by the two brown-rot fungi were compared in this respect. Macroscopically, radiata pine showed more ring and radial checks than Korean red pine. Microscopically, with the progress of decay, spiral checks associated with cross-field pits and bore holes in the cell wall were more remarkably numerous in the radiata pine than in the Korean red pine. In the radiata pine, G. trabeum produced more spiral checks in the cell wall than T. palustris. In the advanced stages of decay by G. trabeum, the erosions of ray cell walls were identified both in the Korean red pine and radiata pine but $S_3$ layers of tracheid walls were eroded only in the Korean red pine.

• Journal of the Korean Wood Science and Technology
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• v.44 no.5
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• pp.726-735
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• 2016

This study was carried out to evaluate the high-temperature drying characteristics of douglas-fir, hemlock, and radiata pine square timber with dimensions of thickness 15 cm and 18 cm. As a result, radiata pine showed the lowest final moisture content followed by douglas-fir and hemlock without reference to the timber size. Moreover, when the longitudinal kerfing is processed, the final moisture content was lower than control. The kerfing treatment was effective to decreasing the twist of radiata pine and hemlock. When douglas-fir is processed to the shape like the edge-grained timber that does not include the pith, the decrease of drying defect was possible.

• Journal of the Korean Wood Science and Technology
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• v.39 no.4
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• pp.311-317
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• 2011

The mechanical properties of heat-compressed Radiata pine (Pinus radiata D.Don) by compression set were investigated. Heat-compression condition was temperature at $180^{\circ}C$ and press time for 60 minutes. The mechanical properties of heat-compressed wood increased with increasing compression set. Increase of the specific gravity has led to increase in mechanical properties. The maximum compression set of Radiata pine was investigated approximately 65%. It was almost same result with porosity 68% of Radiata pine in specific gravity 0.48.

• Mycobiology
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• v.30 no.1
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• pp.37-40
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• 2002

The susceptibility of radiata pine sapwood to fungal attack and the ability of selected fungicides to control colonization of sapstain and mold fungi on green radiata pine sapwood were evaluated. Radiata pine sapwood was highly susceptible to fungal staining, suggesting that prompt application of fungicides after sawing is essential for preventing fungal colonization. The ability of commercial fungicides to prevent fungal discoloration on radiata pine sapwood was assessed using an accelerated 6-week test on small samples in the laboratory, and in field tests using bulk-piled boards exposed outdoors for 6 weeks during summer rainy season. In laboratory tests, Hylite extra provided excellent protection against fungal discoloration even at the lowest concentrations. Hylite clear, Britewood S, and NP-1 Plus provided good short-term protection(2 to 4 weeks), but higher chemical loadings were, required for long-term protection(6 weeks). Woodguard produced little or no protection over the test periods. In field tests, Kathon 893 provided markedly superior protection at the concentration of 0.5 percent or higher. NP-1 Plus provided relatively good protection at all concentrations evaluated. Hylite extra was effective only for short-term protection(2 to 4 weeks) at all concentrations tested, but higher solution strengths were needed for longterm protection.

• Journal of the Korean Wood Science and Technology
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• v.48 no.6
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• pp.861-868
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• 2020

The use of polyphenol extracts from radiata pine (Pinus radiata) bark as raw materials for bio-foams was investigated along with the optimal NaOH extraction conditions. The targeted yield of alkaline extracts was 60%, and the targeted pH was 11 to 12. The radiata pine bark was composed of 70% of a 1% NaOH extract, which contained mainly polyphenols, such as proanthocyanidin (PA). As the particle size of the bark decreased, the yield of the 1% NaOH extracts increased from 57 to 87%. A range of NaOH concentrations, liquor ratios, and extraction times were explored to establish an economic polyphenol extraction method. More than 60% of the alkaline extract was extracted, and the pH of the extract was approximately 12 when the optimum extraction conditions were employed, i.e., a liquor to bark ratio of 5:1, a NaOH dosage of 17 to 18% based on the bark weight, and a 1 h extraction time. Following neutralization of the alkaline extract, structural analysis indicated severe structural changes in the PA during the alkaline extraction. Because the alkaline extract was barely soluble in the solvent used for the structural analyses, it is assumed that chemical modification is required to increase the solubility of the alkaline extract for the production of bio-foams.

• Journal of the Korean Wood Science and Technology
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• v.24 no.4
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• pp.1-6
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• 1996

Extracts from bark have been studied with a view to producing water-proof wood adhesives. Lately many softwoods, such as radiata pine from New Zealand and larch from Siberia, Russia, have been imported and utilized, and their residual barks would be expecting as potential raw materials for something useful chemicals. The great effort toward utilization of bark extractives as a chemical feedstock has been made on a worldwide level. However few report has been done for the utilization of tree bark extractives in Korea. Hot-water extracts were prepared from barks of Japanese larch(Larix leptolepis). Siberian larch(Larix gmelinii) and Radiata pine(Pinus radiata). The effect of various factors, such as particle size, liquor ratio, extraction temperature, and reaction time, on the extractive yields was discussed. Particle sizes affected the hot-water extractives: the finer the particle size, the higher extractives and extract efficiency. Higher temperature and higher liquor ratio were more effective. Extractives from Japanese larch were relatively less than those from Siberian larch and Radiata pine barks. Formaldehyde precipitates was the highest in extractives of Radiata pine barks. It could be concluded that Siberian larch bark was the best raw material for tannin adhesives, because its extractive yield was higher than those of the other barks.

• Journal of the Korean Wood Science and Technology
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• v.39 no.4
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• pp.303-310
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• 2011

The mechanical properties of heat-compressed Radiata pine (Pinus radiata D.Don) by compression temperature and time were investigated. The compressive strength and bending strength of heat-compressed wood increased with increasing compression temperature and time. But the compressive strength and bending strength decreased with press temperature $220^{\circ}C$. It was considered due to thermal degradation during high temperature conditions. The surface hardness of heat-compressed wood increased with increasing compression temperature. However, the effect of compression time was negligible. The nail holding power was not affected by compression temperature and time.

• Food Science and Biotechnology
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• v.15 no.3
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• pp.424-430
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• 2006

Low molecular weight polyphenols were isolated from hot water extracts of radiata pine (Pinus radiata) bark using a Sephadex LH-20 column and characterized by $^1H$ and $^{13}C$ NMR, UV, FT-IR, and GC-MS analyses. Major compounds isolated and identified were protocatechuic acid, trans-taxifolin, and quercetin. Trans-taxifolin, an important intermediate in biosynthetic route of proanthocyanidin (PA), was isolated in large quantities and indicates that PA is a major component of radiata pine bark. Small amounts of polyphenols were identified by GC-MS analysis. The presence of p-hydroxybenzoic acid, vanillic acid, protocatechuic acid, cis- and trans-feruic acid, p-coumaric acid, trans-caffeic acid, (-)-epicatechin, (+)-catechin, trans- and cis-taxifolin, (+)-gallocatechin, and quercetin was confirmed by comparison of mass fragmentation patterns and retention times (RT) with authentic samples. In addition, the presence of astringenin, astringenin glycoside, trans- and cis-leucodelphinidin was strongly assumed from characteristic mass fragment ions due to their conjugated structure and retro Diels-Alder reaction, and also from biosynthetic route of PA. GC-MS analysis allowed us to detect small amounts of phenolic acids and flavonoids and eventually discriminate trans- and cis-configuration in the identified polyphenols.

• Journal of the Korean Wood Science and Technology
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• v.24 no.1
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• pp.34-47
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• 1996

Veneers of two nominal thicknesses, 1.5 and 2.5mm, were rotary peeled from Japanese larch (Larix leptolepis). Dahurian larch (Larix gmelinei) and Radiata pine (Pinus radiata) bolts unheated and heated in the water vat temperature of $66^{\circ}C$ by rising a final temperature at 10cm core of $60^{\circ}C$ to remain core diameter of 11.4cm. 1.5 and 2.5mm thick veneer cut from the heated Japanese larch were significantly thinner than those of the unheated bolt and 2.5mm thick veneer cut from the heated Dahurian larch were significantly thicker than that of the unheated bolt. 1.5mm thick Dahurian larch veneer and 1.5 and 2.5mm thick Radiata pine veneers showed insignificant difference between the unheated and heated bolts, respectively. Check distance on the loose side of 1.5mm thick veneer cut from the heated Radiata pine was significantly wider than that of the unheated bolt. However check distances on the loose side of 1.5 and 2.5mm thick Japanese larch and Dahurian larch veneers and 2.5mm thick Radiata pine veneers showed insignificant difference between the unheated and heated bolts. Also the depth of check on the loose side of three species showed insignificantly difference between the unheated and heated bolts. Arithmatic mean deviation($R_a$) and maximum height($R_{max}$) of the profile on the loose side of dried veneer by preheating the bolt compared with unheated bolts were different among apecies and between veneer thickness. The preheating treatment slightly affected qualities of these thin veneers such as 1.5 and 2.5mm. The yield of 2.5mm thick veneer from the heated radiata pine was significantly higher than that of the unheated bolt. However the yield of 2.5mm thick veneer for other two species and 1.5mm thick veneer for three species showed insignificant difference between the unheated and heated bolts. The yield of 2.5mm thick veneer for three species were higher than those of 1.5mm thick veneer. The average yields of green veneer of Japanese larch. Dahurian larch and Radiata pine were 57.1, 55.1 and 54.0 percent, respectively. Variables such as initial MC. drying time and veneer thickness had strong effect for Japanese larch veneer, less effect for Radiata pine veneer and nuch less effect on final MC for Dahurian larch veneer in jet drying. Correlation between the current MC and the drying time of Dahurian larch with low variation of initial MC was higher than those of Japanese larch and Radiata pine veneer with high variation of initial MC in high temperature drying. Thickness shrinkages of 2.5mm thick veneer for Japanese larch and Radiata pine were higher than those of 1.5mm thick veneers, but shrinkages of Dahurian larch veneer were similar between two nominal veneer thicknesses.

• Journal of the Korean Wood Science and Technology
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• v.35 no.2
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• pp.79-84
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• 2007

Surface mold fungi growing on CCA-treated wood could be inhibited effectively by the incorporation of moldicide into treating solution. In this study, moldicides compatible with the CCA solutions from various commercial moldicides were screened, and then their optimum concentrations for controlling surface mold on CCA-treated radiata pine sapwood were examined through both the laboratory and the field trials. Among nine commercial moldicdes tested, two substituted isothiazolinones, moldicide A containing 2-n-octyl-4-isothiazoline-3-one and moldicide B containing 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one, were chemically compatible with CCA solution. The optimum concentration to be incorporated into 2% CCA treating solution was determined to be 0.001% for moldicide A and 0.003% for moldicide B.